1. Field of the Invention
The invention relates to a safety binding for an alpine ski which is adapted to retain the end of a boot, supported against the ski, and to release the end of the boot when it exerts an excessive force exceeding a predetermined threshold.
More precisely, the invention relates to a safety binding of this type, which is adapted to ensure the release of the boot at least in a lateral direction. Normally, such a binding is a front binding for retaining the front of the boot.
2. Description of Background and Relevant Information
It is known to equip front bindings with a support plate, on which rests the front of the boot. Generally, this support plate is equipped with means to limit the friction which is exerted principally between the boot and the ski or the boot and the jaw of the binding when the boot is laterally released.
Thus, it is known to mount a fixed support plate on the ski with a layer of anti-friction material on its upper portion, for example, a small plate of polytetrafluoroethylene. Such a construction is described in French Patent 2,128,012.
It is generally known to equip the front binding with a movable support plate, which is mechanically connected to the jaw of the binding, and which is displaced therewith. Such a construction is described, for example, in German Application DE-OS 3,005,761.
Another construction includes mounting a support plate at the rear of the binding which is movable independently of the elements of the binding. Abutments limit the lateral displacement of the support plate. Such a construction is described, for example, in Swiss Patent 431,349.
This construction is preferred because the support plate moves With the boot during a lateral release. Thus, the friction between the boot and the ski is transferred between the support plate and the ski. This friction thus does not depend on the state of the surface of the sole of the boot, which can be very variable depending upon the extent of wear.
Likewise, this construction is preferred because there is an independence between the movement of the support plate and the elements of the binding. Thus, if the support plate refuses to move laterally, for example, as a result of sticking due to ice, or a foreign body which impedes its movement, this does not disturb the operation of the binding contrary to the preceding case where this can prevent the binding from laterally opening.
Reference is also made to U.S. Pat. No. 4,911,464.
There is likewise known, according to German Application DE-OS 3,624,387, a movable support plate which is equipped with linkage means with the elements of the jaw. These linkage means ensure the return of the movable plate to the centered position after a lateral release.
It is more precisely these latter types of movable plates equipping a front binding to which the invention aims at providing improvements.